Skeletons, footprints, and foot art reveal high status associated with a sixth digit.
Five fingers and five toes are the norm for humans, though once in awhile a baby is born with an extra digit. According to a new study in the journal American Antiquity, if you were lucky enough to be born with a sixth toe in Chaco Canyon, New Mexico about a thousand years ago, that might have earned you special status in society.
Polydactyly — a congenital physical anomaly in which humans or animals have excess fingers or toes — was known to be common among the prehistoric Chacoan people based on their cave art and skeletal remains, but until now, archaeologists didn’t just how common it was.
Researchers analyzed 96 skeletons that had previously been excavated from the canyon’s sacred Pueblo Bonito site. Three of the 96 skeletons bore sixth toes, and for each of these polydactyl individuals, the extra toe was on the little toe side of the right foot.
That means around 3.1 percent of the population at Chaco had polydactyly, which is a 15.5 times higher rate than what occurs in modern Native Americans.
Why so many of the Chacoan people were polydactyl is a bit of a mystery. Though the trait is primarily under genetic control, it cannot be explained by inbreeding, which exposes uncommon recessive traits, as polydactyly is actually a dominant trait. In most cases, it is not caused by a genetic disease.
Study co-author Kerriann Marden offers the possibilities that exposure of pregnant females in Chaco Canyon to some hazardous substance, or certain aspects of their diet while pregnant, might explain the prevalence of this trait, National Geographic reports.
Regardless of the cause, excavations of the site have revealed intriguing clues about how these 6-toed individuals were regarded in society.
Footprints and handprints were commonly stamped into the walls and floors of the great houses of Chaco Canyon. The prints near entrances to the ritual rooms and around ceremonial structures were mostly polydactyl, suggesting that these extra digits were honored.
The burials of those with polydactyly are also telling. One skeleton was found with an anklet on its six-toed foot, while no jewellery adorned its five-toed foot.
Lead author Patricia Crown, from the University of New Mexico, tells National Geographic, “We found that people with six toes, especially, were common and seemed to be associated with important ritual structures and high-status objects like turquoise.”
“This was an important part of the past,” says Crown, noting that polydactyl individuals “were treated as special, and they were treated with a lot of respect.”